Usage:
D250E (5TN),
D300E (7FN) Articulated Trucks
Reference: Service Manual Module, SENR8653-01; Disassembly & Assembly; D250E & D300E Articulated Trucks Powertrain; "Disassemble & Assemble Front, Center, & Rear Differentials"; Steps 45, 46, and 47; Page 178. This module is part of Service Manual SENR8650.
The text, in Steps 45, 46, and 47, should be replaced by the following, which takes into account the different directions for the front bevels as compared to the center and rear bevels.
45. After the backlash and preload adjustment have been made, the tooth contact pattern between the pinion shaft and the bevel gear must be checked. Perform the following procedure to adjust the tooth contact pattern:
Figure 1.
Correct tooth pattern.
a) The tooth contact between bevel pinion and gear must be checked by turning the bevel pinion shaft in both directions after coating the bevel gear teeth with a small amount of Prussian blue, red lead, or paint.
b) The correct area of tooth contact starts near the inside end of the teeth of the bevel gear and goes a maximum of 50 percent of the length of the teeth. See Figure 1 for an example of the correct area of tooth contact.
NOTE: As Steps 46 and 47 are performed, the spiral direction of the bevel gear being adjusted may be opposite of Figures 2 and 3. The steps below still apply except the convex and concave sides of the gear will be reversed.
Figure 2.
Incorrect tooth contact.
46. If the tooth contact pattern is not correct, then shim adjustments need to be made. Note patterns of contact on the convex versus the concave side of the gear teeth. If tooth contact is high on the concave side and low on the convex side as in Figure 2, perform the following procedure:
a) Remove some shims from shim pack (43).
b) Repeat Steps 39 through 42.
c) Then, repeat Step 43.
Figure 3.
Incorrect tooth contact
47. If tooth contact is low on the concave side and high on the convex side as in Figure 3, then perform the following procedure:
a) Add some shims to shim pack (43).
b) Repeat Steps 39 through 42.
c) Then, repeat Step 43.